A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: mpc755 on 20 Feb 2010 23:57 On Feb 20, 11:13 pm, artful <artful...(a)hotmail.com> wrote: > On Feb 21, 2:59 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > On Feb 20, 10:45 pm, "Peter Webb" > > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > > "mpc755" <mpc...(a)gmail.com> wrote in message > > > >news:7cfe6937-1504-456f-8ea0-4e80f55a6bea(a)c28g2000vbc.googlegroups.com.... > > > On Feb 20, 8:35 pm, "Peter Webb" > > > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > > > > ______________________________________ > > > > > Here's a much simpler question, which has no mirrors, trains, > > > > > embankments, > > > > > lightning etc. > > > > > > Lets say the earth is moving relative to the ether at speed v. We > > > > > measure > > > > > the speed of light in a vacuum on earth in the direction in which the > > > > > earth > > > > > is moving through the ether. What do we measure the speed of light to be > > > > > in > > > > > that laboratory on earth? c? c+v? c-v? Something else? > > > > > The speed of light is 'measured' to be 'c'. It depends on the state of > > > > the laboratory on Earth with respect to the aether if the speed of > > > > light is 'c' with respect to the laboratory in nature. Since the > > > > aether is at rest, or almost at rest, with respect to the surface of > > > > the Earth, > > > > > ______________________________________ > > > > Ohh yeah. That's a pretty unfortunate co-incidence. So lets wait 6 months > > > > until August 21st 2010; the earth will have moved 180 degrees in its orbit > > > > around the Sun and be moving the the opposite direction, and hence have a > > > > relative speed to the to ether of 60 kms/sec. What is the measured speed > > > > of > > > > light in a laboratory on earth moving at speed 60 kms/sec relative to the > > > > ether? > > > > What part of the aether is at rest with respect to the surface of the > > > Earth are you unable to understand? > > > > _________________________________ > > > You mean the surface of the earth is *always* at rest with respect to the > > > ether? > > > > What happens if we repeat the experiment in a laboratory in low earth orbit? > > > That will be moving at a speed of about 25,000 kph relative to the earth and > > > hence to the ether. > > > If the laboratory is moving at 25,000 kph relative to the Earth the > > laboratory is not moving at 25,000 kph relative to the aether is less > > at rest with respect to the surface of the Earth at 25,000 kph than it > > is on the surface of the Earth. > > By how much? > > Would it be at rest WRT the orbiting laboratory? > > > > > The analogy is if you go outside and you feel no wind and the trees > > are not moving you can still look up in the sky and see clouds moving > > past. The aether 'flows' east to west and gets less at rest with > > respect to the surface of the Earth the further from the surface of > > the Earth the aether is. > > > > What will be the measured speed of light in this case, > > > in a stallite in LEO ? > > > > > and since I am assuming the laboratory exists on the > > > > surface of the Earth, then the light waves in the laboratory are > > > > propagating at 'c' with respect to the aether which is at rest with > > > > respect to the laboratory. So, in this situation, the light waves are > > > > physically propagating at 'c' with respect to the laboratory. > > > > And if conducted in a laboratory in low earth orbit, with a relative speed > > > of 25,000 kph relative to the ether - what will be the measured speed of > > > light then? > > > The light will be 'measured' to be 'c'. > > So the lab must again at rest wrt the aether. > > > If the Observers in the > > laboratory in low Earth orbit know how they are moving with respect to > > the aether they will be able to determine the speed of light to be 'c' > > with respect to the aether. > > You just contradicted yourself .. you said the speed of light will be > c, so that must mean they are at rest wrt the aether. > I did not say the speed of light 'is' 'c', I said the speed of light in the laboratory will be 'measured' to be 'c'. > The question asked was NOT the speed wrt the aether, but what is the > speed of light relative to the lab? > > What about in a train moving on the earth's surface .. would the > aether be at rest relative to the train as well as the earth? The train is full of flat bed cars and the flat bed cars run under the water and do not disturb the water. Flashes of light occur in the water at A' and B'. The light waves propagate with respect to the water, not the train. The three Observers get together and synchronize their clocks. The clocks consist of paddles for the second hand. As the Observer walks the clock to B' the clock is being walked against the flow of the water and 'ticks' slower, due to the increase in the water pressure on the clock, than the clock at M' and the clock being walked to A'. The clock being walked to A' is being walked with the 'flow' of water and is under less water pressure and 'ticks' faster than the clocks at M' or being walked to B'. When the clocks stop being walked and are A', M', and B' they all 'tick' at the same rate because they all exist in the same amount of water pressure. When the flashes of light occur and when the reach the Observers and based upon the time their clocks state the Observers would conclude the light traveled through water as 'if' it were at rest with respect to the train. > > Is there ANYWHERE that the aether is NOT at rest wrt some laboratory > there? If the aether is at rest with respect to the embankment and the train and the embankment both occupy the same three dimensional space and the train is moving relative to the embankment then the train is not at rest with respect to the aether. But, the Observers on the train will still determine the light to have traveled at 'c' with respect to the train due to their clocks being unsynchronized due to their being walked against the 'flow' of the aether or with the 'flow' of the aether to B' and A', respectively.
From: mpc755 on 21 Feb 2010 00:01 On Feb 20, 11:21 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > And if conducted in a laboratory in low earth orbit, with a relative speed > > of 25,000 kph relative to the ether - what will be the measured speed of > > light then? > > The light will be 'measured' to be 'c'. If the Observers in the > laboratory in low Earth orbit know how they are moving with respect to > the aether they will be able to determine the speed of light to be 'c' > with respect to the aether. > > ______________________________________ > So, according to you, in every inertial reference frame, the measured speed > of light is "c", completely independent of how the observer is moving > relative to the ether? Measured, yes. If the train and embankment occupy the same three dimensional space and the aether is at rest with respect to the embankment and the train is moving relative to the embankment then the aether is not at rest with respect to the train. Light waves associated with the lightning strikes at A/A' and B/B' will be measured to be 'c' by the Observer at M' on the train and measured to be 'c' by the Observer at M on the embankment even though the light waves propagate at 'c' with respect to the aether.
From: Peter Webb on 21 Feb 2010 00:25 Just to confirm your belief, do you agree with the following statement: 'If any observer in any inertial reference frame measures the speed of light from within that frame, they will always get the value "c" irrespective of their speed relative to the ether.' Do you agree? If not, what part do you disagree with? Note this is not a statement about what the speed of light "really is", it is purely about the outcome of a physical experiment where the speed of light is actually measured.
From: Peter Webb on 21 Feb 2010 00:27 "mpc755" <mpc755(a)gmail.com> wrote in message news:1c9cf786-36cc-4fce-8b57-7f45f5b88ddd(a)v1g2000yqk.googlegroups.com... On Feb 20, 11:21 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > And if conducted in a laboratory in low earth orbit, with a relative > > speed > > of 25,000 kph relative to the ether - what will be the measured speed of > > light then? > > The light will be 'measured' to be 'c'. If the Observers in the > laboratory in low Earth orbit know how they are moving with respect to > the aether they will be able to determine the speed of light to be 'c' > with respect to the aether. > > ______________________________________ > So, according to you, in every inertial reference frame, the measured > speed > of light is "c", completely independent of how the observer is moving > relative to the ether? Measured, yes. ____________________________________ OK, is the speed of light measured as 'c' in every inertial reference frame?
From: mpc755 on 21 Feb 2010 06:43
On Feb 21, 12:27 am, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "mpc755" <mpc...(a)gmail.com> wrote in message > > news:1c9cf786-36cc-4fce-8b57-7f45f5b88ddd(a)v1g2000yqk.googlegroups.com... > On Feb 20, 11:21 pm, "Peter Webb" > > > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > > And if conducted in a laboratory in low earth orbit, with a relative > > > speed > > > of 25,000 kph relative to the ether - what will be the measured speed of > > > light then? > > > The light will be 'measured' to be 'c'. If the Observers in the > > laboratory in low Earth orbit know how they are moving with respect to > > the aether they will be able to determine the speed of light to be 'c' > > with respect to the aether. > > > ______________________________________ > > So, according to you, in every inertial reference frame, the measured > > speed > > of light is "c", completely independent of how the observer is moving > > relative to the ether? > > Measured, yes. > > ____________________________________ > OK, is the speed of light measured as 'c' in every inertial reference frame? Measured, yes. But it is the reason why it it measure to be 'c' which is the important part when discussing what occurs physically in nature. The 'reference frame' is moving with respect to the aether. When Observers synchronize clocks and then move to their respective destinations they are not moving the same with respect to the aether. As in the train example, the Observer moving towards B' is moving against the 'flow' of the aether and their clock 'ticks' slower than the clock at M'. The Observer moving towards A' is moving with the 'flow' of aether and their clock 'ticks' faster than the clock at M'. This unsynching of the clocks offsets the fact the light propagates at 'c' with respect to the aether. A flash of light at M' will reach A' and then B' but the clocks at A' and B' will read the same due to their not be synchronized. The light will be reflected by mirrors and now travel in the exact opposite direction in terms of the 'flow' from A' back to M' and from B' back to M' so the light waves reach M' simultaneously. Flash of light occurs at M'. Light waves propagate with the 'flow' of aether towards A' and propagate against the 'flow' of aether towards B'. The light waves arrive at A' prior to arriving at B', in nature. But the time on each clock will read the same when the light arrives. The light waves then reflect off a mirror at A' and propagate against the 'flow' of aether towards M' and the light waves then reflect off a mirror at B' and propagate with the 'flow' of aether towards M'. The light from A' and B' arrives back at M' simultaneously. The Observers measure the speed of light to be 'c' while at the same time the light waves have propagated at 'c' with respect to the aether. |